During point-to-point conference between TE60 and Polycom HDX7000 sound lost appeared. If you are counting on TE60 side: "1,2,3,4,5,6,7,8", far end participant hears: "1,2,3,..,5,6,...,8". It means sound lost partly. It doesn't matter how loud or how long words have been pronounced. Every time part of voice stream is lost.
TE60 software version: V500R002C00SPCb00
No alarms appear on TE60.
1) To check if the issue is related to far end participant or it's local issue, I hold local auioloop testing. Durinf local audio loopback testing the sound lost issue reappears. It means the issue is related to local end, TE60. Change microphone sensitivity, speakers loudness, sound effects in TE60 WEB-interface don't affect on sound lost.
2) To check if VPM220 is broken, it was replaced with new one. The issue reappears. Then VPM220(wired) was replaced with VPM220W(wireless). The issue reappears.
3) To check the issue is related to TE60 or to VPM220, TE60 was replaced with new one. The issue reappears.
The root cause is echo cancellation algorithm of TE60 V500R002C00SPCb00 software version works not well.
TE60 software upgrade from V500R002C00SPCb00 to TE60 V600R006C00SPC500. The issue has been resolved both for conference with HDX7000 and for local audio loopback testing on TE60.